hi Hilly

you can search for "dmg" in these forums to find more info, but Disk Copy (Jaguar) or Disk Utility (Panther) can open .dmg files and mount them as a disk images on the desktop. If you are using OS 9 or earlier, you're pretty much out of luck, since .dmg are mostly for OSX.

btw--I assume you used the file name as an example: otherwise, if it is a copyright program, you should go to the site for help, not here.

cheers